diff --git a/reduction_tools/stream_random.py b/reduction_tools/stream_random.py
new file mode 100644
index 0000000..2a77110
--- /dev/null
+++ b/reduction_tools/stream_random.py
@@ -0,0 +1,183 @@
+#!/usr/bin/env python3
+
+# author J.Beale
+
+"""
+# aim
+randomly select a series of crystals from a stream file and
+then compile them into the correctly formated .stream
+
+# usage
+python stream_random.py -s <path to stream>
+                        -o output file names
+                        -n sample size
+                        -r how many repeat random samples do you want?
+
+# output
+.stream file with random sample of xtals
+"""
+
+# modules
+import re
+import argparse
+import pandas as pd
+import numpy as np
+import os
+
+def scrub_cells( stream ):
+
+    # get uc values from stream file
+    # example - Cell parameters 7.71784 7.78870 3.75250 nm, 90.19135 90.77553 90.19243 deg
+    # scrub clen and return - else nan
+    try:
+        pattern = r"Cell\sparameters\s(\d+\.\d+)\s(\d+\.\d+)\s(\d+\.\d+)\snm,\s(\d+\.\d+)\s(\d+\.\d+)\s(\d+\.\d+)\sdeg"
+        cell_lst = re.findall( pattern, stream )
+        xtals = len( cell_lst )
+        if AttributeError:
+            return cell_lst, xtals
+    except AttributeError:
+        logger.debug( "scrub_cells error" )
+        return np.nan
+
+def extract_chunks( input_file ):
+
+    # setup
+    chunk_df = pd.DataFrame()
+    image_no = []
+    chunks = []
+    hits = []
+    collect_lines = False
+    # Open the input file for reading
+    with open(input_file, 'r') as f:
+        for line in f:
+
+            # Check for the start condition
+            if line.startswith('----- Begin chunk -----'):
+                hit = False
+                collect_lines = True
+                chunk_lines = []
+            if collect_lines:
+                chunk_lines.append(line)
+            
+            # find image_no
+            if line.startswith( "Event:" ):
+                image_search = re.findall( r"Event: //(\d+)", line )
+                image = int(image_search[0])
+                image_no.append( image )
+            
+            # is there a hit in chunk
+            if line.startswith( "Cell parameters" ):
+                hit = True
+
+            if line.startswith('----- End chunk -----'):
+                collect_lines = False  # Stop collecting lines
+                chunks.append( chunk_lines )
+                hits.append( hit )
+    
+    chunk_df[ "chunks" ] = chunks
+    chunk_df[ "image_no" ] = image_no
+    chunk_df[ "hit" ] = hits
+
+    # sort values and set image_no as index
+    chunk_df = chunk_df.sort_values( "image_no" )
+    chunk_df = chunk_df.set_index( "image_no" )
+
+    return chunk_df
+
+def extract_xtals( chunk ):
+
+    # setup
+    xtals = []
+    collect_crystal_lines = False
+    # Open the input file for reading
+    for line in chunk:
+
+        # Check for the xtals start condition
+        if line.startswith('--- Begin crystal'):
+            collect_crystal_lines = True
+            xtal_lines = []
+        if collect_crystal_lines:
+            xtal_lines.append(line)
+        if line.startswith('--- End crystal\n'):
+            collect_crystal_lines = False  # Stop collecting lines
+            xtals.append( xtal_lines )
+
+    return xtals
+
+def extract_header( chunk ):
+
+    # setup
+    header = []
+    collect_header_lines = False
+    # Open the input file for reading
+    for line in chunk:
+
+        # Check for the xtals start condition
+        if line.startswith('----- Begin chunk -----'):
+            collect_header_lines = True
+            header_lines = []
+        if collect_header_lines:
+            header_lines.append(line)
+        if line.startswith('End of peak list'):
+            collect_header_lines = False  # Stop collecting lines
+            header.append( header_lines )
+
+    return header
+
+
+def main( input_file ):
+
+    # extract chunks
+    print( "finding chucks" )
+    chunk_df = extract_chunks( input_file )
+    # display no. of chunks
+    print( "found {0} chunks".format( len(chunk_df) ) )
+    print( "found {0} crystals".format( chunk_df.hits.sum() ) )
+    print( "done" )
+
+    # extract xtals
+    print( "geting xtal data from from chunks" )
+    xtal_df = pd.DataFrame()
+    counter = 0
+    for index, row in chunk_df.iterrows():
+
+        chunk, hit, image_no = row[ "chunks" ], row[ "hit" ], row[ "image_no" ]
+
+        if hit:
+        
+            # find xtals and header
+            header = extract_header( chunk )
+            xtals = extract_xtals( chunk )
+
+            # make header same length as xtals
+            header = header*len(xtals)
+
+            # concat results
+            xtal_df_1 = pd.DataFrame()
+            xtal_df_1[ "header" ] = header
+            xtal_df_1[ "xtals" ] = xtals
+            xtal_df_1[ "image_no" ] = image_no
+            xtal_df = pd.concat( ( xtal_df, xtal_df_1 ) )
+
+            # add count and print every 1000s
+            counter = counter + len(xtals)
+            if counter % 1000 == 0:
+                print( counter, end='\r' )
+    print( "done" )
+
+
+def list_of_floats(arg):
+    return list(map(int, arg.split(',')))
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "-s",
+        "--stream",
+        help="input stream file",
+        required=True,
+        type=os.path.abspath
+    )
+    args = parser.parse_args()
+    # run main
+    main( args.stream )